Rodrigo S. Lopes

Delay-time inspection model with dimensioning maintenance teams

We propose a inspection policy based on the delay time concept.We consider the number of maintenance teams for emergency demands as a decision variable.We illustrate the use of the model in a real situation involving a lessee and a leasing company.We highlight the practical impacts of the model by calculating different scenarios (parameters).We highlight the contribution provided by the proposed model. Due to the increase in using equipment in various construction activities, planning the maintenance of this equipment has become extremely important as this aids meeting project deadlines. Alternatively, builders can lease equipment, an option that, in addition to having the advantage of gaining access to the best available technologies at feasible cost, also benefits from the fact that providing maintenance is a contractual obligation of the lessor company. In this context, it must establish a maintenance policy to support the lessee company at an acceptable cost. Thus, this paper proposes a policy for developing an inspection program and forming inspection and maintenance response teams. The application of these concepts targets supporting maintenance planning by equipment-leasing companies in the construction industry.

A general inspection and opportunistic replacement policy for one-component systems of variable quality

We model the influence of opportunities in a hybrid inspection and replacement policy. The base policy has two phases: an initial inspection phase in which the system is replaced if found defective; and a later wear-out phase that terminates with replacement and during which there is no inspection. The efficacy of inspection is modelled using the delay time concept. Onto this base model, we introduce events that arise at random and offer opportunities for cost-efficient replacement, and we investigate the efficacy of additional opportunistic replacements within the policy. Furthermore, replacements are considered to be heterogeneous and of variable quality. This is a natural policy for heterogeneous systems. Our analysis suggests that a policy extension that allows opportunities to be utilised offers benefit, in terms of cost-efficiency. This benefit is significant compared to those offered by age-based inspection or preventive replacement. In addition, opportunistic replacement may simplify maintenance planning.

Multicriteria Model to Support Maintenance Planning in Residential Complexes under Warranty

AbstractBuilding-maintenance decisions are a challenge for most builders. When builders finish construction, there is a guarantee period during which maintenance is their responsibility. These decisions have an effect that go beyond the financial aspects of maintenance costs, because failures during the warranty period are reflected in customer satisfaction and may have an effect on future sales. Thus, maintenance strategies should be devised with a focus on how to best deploy them to optimize both savings and occupant satisfaction. For this purpose, the present paper proposes a multicriteria model based on the delay-time concept to provide the builder with a quantitative tool to support the definition of a maintenance-inspection policy. An illustration of the application of the model is demonstrated, providing good results that support the decision maker in setting a better inspection policy.

Opportunistic Maintenance Policy for a System with Hidden Failures: A Multicriteria Approach Applied to an Emergency Diesel Generator

This paper aims to develop a maintenance policy to support the maintenance decisions of an emergency system that supplies electricity when failure of the primary system occurs in a health facility. An Opportunistic maintenance policy was developed, in which failures are hidden and inspections are performed to detect the state of the system and subsystems. Failure in the system can have negative consequences for the health unit. A multicriteria model that considers cost and availability criteria and preference of the maintenance manager of the health unit was developed.

Integrated model of quality inspection, preventive maintenance and buffer stock in an imperfect production system

Abstract In this study, the influence of a quality inspection policy on an imperfect production system in which a percentage of the produced items is inspected is modelled. The inspection policy is imperfect, permitting type I and type II errors. Items are shipped for sale with a free minimal repair warranty policy. After each production cycle, preventive maintenance is performed. In case of failure in the production process before the cycle’s end, a minimal repair is indicated. A buffer stock is established to meet demand while preventive maintenance is performed. We also considered that defective items detected on inspection are sent for reworking. The model is formulated with the objective of minimizing the total cost expected per item while considering an average outgoing quality constraint. Subsequently, we present a numerical experiment to illustrate the proposed model. The results indicate that the probability of type I and type II inspection errors has a significant impact on optimal production and the percentage of items inspected.